Sustainable EcoGuardian

Inspiration We're a team of four, and we noticed that when you book travel you always see the price, but never the carbon cost. We wanted to make the environmental impact of a trip just as easy to see — for anyone, not just companies — so choosing a greener option becomes an actual decision instead of a guess.

What it does Sustainable Travel Guardian helps people plan lower-carbon trips. You can estimate a trip's CO₂e with a carbon calculator, compare rail vs. air on both emissions and travel time, generate a simple travel policy, and track emissions over time.

How we built it We built it with React, TypeScript, and TanStack Start, styled with Tailwind CSS. Supabase handles authentication and the database. We added a small MCP server that exposes our core logic (like the footprint estimator and rail-vs-air comparison) as tools an AI assistant can use. We split the work across the four of us and kept everything in GitHub.

What we learned How carbon estimates actually work — mode, distance, and class matter more than any single number. Keeping the frontend and database types in sync with TypeScript, which saved us from a lot of bugs. How to divide features across a team and keep a shared branch working. Challenges we faced Making the emissions numbers realistic and easy to trust. Keeping types consistent between Supabase and the app as things changed. Broadening the app beyond business travel after we'd already started building it. Coordinating four people on one codebase (including fixing a messed-up Git setup early on).